1. Field of the Invention
Embodiments of the present invention generally relate to an apparatus and a method for processing semiconductor substrates. More particularly, embodiments of the present invention provide an apparatus and a method for cleaning semiconductor substrates.
2. Description of the Related Art
During fabrication of a semiconductor device, various layers, such as oxides, copper, require planarization to remove steps or undulations prior to formation of subsequent layers. Planarization is typically performed mechanically, chemically, and/or electrically by pressing the device side of a semiconductor substrate against a polishing pad which is saturated with a polishing solution, such as an abrasive compound, and by rotating the polishing pad relative to the semiconductor substrate. Multiple steps of polishing are generally performed using different polishing pads and polishing solutions to achieve the desired flatness and smoothness on the device side.
The planarization process can be followed by a cleaning process which removes residual of the polishing solutions and/or particles from polishing. Conventional cleaning processes generally include scrubbing the substrate surfaces with mechanical scrubbing devices using brushes made from porous or sponge like materials, such as polyvinyl acetate (PVA), or brushes made with nylon bristles. When cleaning with scrubber brushes, the scrubber brushes generally approach the substrate from both the front side and the back side to contact the substrate and apply a brushing force against the substrate. It is desirable to monitor and control the force applied to the substrate during cleaning to avoid damage to the substrate. However, conventional brush cleaners need improvement in controlling the movement of scrubbing brushes and resulting forces applied to the substrate during cleaning.
Therefore, there is a need for an apparatus and a method for cleaning a substrate using scrubber brushes with motion and force control.